I was going to post this info on an existing subject thread, but I found that those existing ones had mis-spelled the word. So here it is under its new correctly spelled heading. Maybe someone will link those other threads to this one, or this one to those.

I recently received this photo of a 'double aerorig', or we might term it a 'ketch aerorig' from a gentleman who is showing interest in my DynaRig catamaran.

Anyone have any other info?
.....Twin, Double, or Ketch Type Aerorig
....."a yacht built and sailed in Brazil"

....excerpt....
When Brazilian adventurer Amyr Klink attempts a 50,000 mile polar circumnavigation next year, he will catch the wind with two AeroRigs. His new boat Paratii 2, a 28 metre aluminium schooner, is currently being built in Brazil, and Carbospars will supply the rigs at the end of 1999. Klink is an AeroRig convert, after using one on his old 15 metre steel-hulled cruiser, Paratii, on the first ever single-handed circumnavigation around Antarctica. The trip took him just 88 days instead of the expected 100, because the AeroRig made the boat more stable and easier to handle, even in mountainous seas. After 9,700 miles, enduring winds up to 120 kilometres an hour, and waves up to 20 metres high, Klink wrote "I am really pleased with the AeroRig - it keeps the boat well balanced."http://www.raeng.org.uk/news/release....htm?NewsID=83

Carbospars bit the dust due to lousy management. Apart from the last rig they built, their quality was good, although the published weights of their rigs was very high, as were the prices.

As far as I know, we are the only ones building aerorigs, which we call easy rigs. There is a video of one on a 15m/50' harryproa at http://www.youtube.com/watch?v=8chR6DAFjGA Notice the single line to control the angle of both sails, the automatic feathering of the unstayed mast in puffs and the total lack of winches, tracks and jammers to trip over on the deck. This rig weighs 250 kgs/440 lbs including boom, sails and all fittings which is not bad for a 50 footer. There is an extra 20 kgs of beefing up in the hull to support the bearings.

For ease of use, safety, longevity and low maintenance they are pretty hard to beat for cruising boats, and with the addition of runners to the end of the boom have potential for racers as well.

With our cost effective manufacturing techniques and low cost carbon they cost less than conventional rigs if the boat is designed for them from the outset.

I built a rig like this 35 years ago when I was a teenager and needed a cheap sailboat.

I devised a cross like framework to support a mast with a vinyl 4 man raft underneath.

It sailed to windward well with two people on board, but not at all with just one. The boards were not deep enough.

My rig did have stays, though, with the lack of which on this rig seems to be a big engineering mistake. Another mistake I see is not having boom vangs.

I would have one on each end.

Carbon fiber is indeed very strong, but even its strength has limits. The major complaints about this rig seem to be its weight and lack of stiffness.

Vangs, spreaders, stays and shrouds can go a long way toward solving those problems.

It is my humble opinion that unstayed masts belong on either very small boats or very narrow keel boats without a lot of form stability. (such as a folkboat)

The airfoil shaped mast seems to be another mistake. It is useful only if you can line the sail up behind it perfectly. I think it would be much better if the mast were round and the sail attached to it with either hoops or laces.

I know that this is very counter intuitive and would cost several degrees greater tacking angle, but the mast would be much stronger (and probably lighter) and the rig would be far more user friendly. The main part of the sail would than be able to drift over to the leeward side of the mast and the jib part would be able help guide the wind around it.

Sometimes you have to take a step or two backward to move forward.

Even then, I'm afraid, the components of the rig would be too heavy to compete with a more conventional rig. I always saw it as having more potential as a sail assist rig or a primary rig on a sailboat with big fuel tanks and a small engine.

I know it is a bummer in the 21st century to have sailing rigs that resemble the wing spar set ups on early 20th century monoplanes. But sailboats are inherently different from airplanes. No airplane ever capsized because its wing spar was too heavy. Nor has any airplane ever had to shorten its wingspan due to stronger winds. (except for some partially successful 'swing wing' designs, perhaps)

My sail was only about 30sf and it was made out of duct tape and plastic drop cloths. Its mast was a 2x2 and its boom a 1x2. It was held up with tri stay arrangement. It was indeed quite crude. But it was able out point just about every sail of the same size it came across.

I could not disagree more. Stays, spreaders and vangs do indeed make for a stiffer rig, but at a price, in terms of air drag, maintenance, safety and having to replace them after a given time. In contrast, the unstayed rig and boom will last indefinitely and need no maintenance.

We then have the question of whether rigidity is a good thing in a cruising rig. The answer, in my opinion is a categoric no. A rig that automatically eases in a gust is a godsend for a cruiser. Not only is it far safer, but it also allows more sail to be carried for longer, thus making for faster passages.

I am not sure what you mean by the airfoil mast. The mast in the video is round. We are built unstayed airfoil section masts, but they rotate independantly of the mast, thus making them extremely efficient. The current generation also telescope, making them safer in a gale than conventional masts.

The sail on hoops or laced to the round mast makes good sense, although not on a jib rigged boat or a boat that cannot be laid on it's side to rig it. I am currently waiting for the sail on my 7.5m test boat to be recut so i can try this and compare it with a pocket luff.

Your comments on weight are plain wrong. The rig itself is a little heavier, but the centre of gravity is lower. If the boat is designed for the easy rig from the start, it is lighter; much lighter in the case of a multihull.

Your comments on small and narrow boats are also wrong, as the boat (multihull with high righting moment) in the video shows. I don't know of any cruising boats that will sail at wind speed with as little fuss and as much safety as this.

Interpolating from a 35 year old tiny polytarp/scrap timber rig on a vinyl hull to a properly engineered modern rig is a big leap. I suggest you study the rig in the video, or sail on a balanced rig and you may see how things have changed.

regards,

Rob

Quote:

Originally Posted by sharpii2

This all looks very familiar to me.

I built a rig like this 35 years ago when I was a teenager and needed a cheap sailboat.

I devised a cross like framework to support a mast with a vinyl 4 man raft underneath.

It sailed to windward well with two people on board, but not at all with just one. The boards were not deep enough.

My rig did have stays, though, with the lack of which on this rig seems to be a big engineering mistake. Another mistake I see is not having boom vangs.

I would have one on each end.

Carbon fiber is indeed very strong, but even its strength has limits. The major complaints about this rig seem to be its weight and lack of stiffness.

Vangs, spreaders, stays and shrouds can go a long way toward solving those problems.

It is my humble opinion that unstayed masts belong on either very small boats or very narrow keel boats without a lot of form stability. (such as a folkboat)

The airfoil shaped mast seems to be another mistake. It is useful only if you can line the sail up behind it perfectly. I think it would be much better if the mast were round and the sail attached to it with either hoops or laces.

I know that this is very counter intuitive and would cost several degrees greater tacking angle, but the mast would be much stronger (and probably lighter) and the rig would be far more user friendly. The main part of the sail would than be able to drift over to the leeward side of the mast and the jib part would be able help guide the wind around it.

Sometimes you have to take a step or two backward to move forward.

Even then, I'm afraid, the components of the rig would be too heavy to compete with a more conventional rig. I always saw it as having more potential as a sail assist rig or a primary rig on a sailboat with big fuel tanks and a small engine.

I know it is a bummer in the 21st century to have sailing rigs that resemble the wing spar set ups on early 20th century monoplanes. But sailboats are inherently different from airplanes. No airplane ever capsized because its wing spar was too heavy. Nor has any airplane ever had to shorten its wingspan due to stronger winds. (except for some partially successful 'swing wing' designs, perhaps)

My sail was only about 30sf and it was made out of duct tape and plastic drop cloths. Its mast was a 2x2 and its boom a 1x2. It was held up with tri stay arrangement. It was indeed quite crude. But it was able out point just about every sail of the same size it came across.

I could not disagree more. Stays, spreaders and vangs do indeed make for a stiffer rig, but at a price, in terms of air drag, maintenance, safety and having to replace them after a given time. In contrast, the unstayed rig and boom will last indefinitely and need no maintenance.

We then have the question of whether rigidity is a good thing in a cruising rig. The answer, in my opinion is a categoric no. A rig that automatically eases in a gust is a godsend for a cruiser. Not only is it far safer, but it also allows more sail to be carried for longer, thus making for faster passages.

I am not sure what you mean by the airfoil mast. The mast in the video is round. We are built unstayed airfoil section masts, but they rotate independantly of the mast, thus making them extremely efficient. The current generation also telescope, making them safer in a gale than conventional masts.

The sail on hoops or laced to the round mast makes good sense, although not on a jib rigged boat or a boat that cannot be laid on it's side to rig it. I am currently waiting for the sail on my 7.5m test boat to be recut so i can try this and compare it with a pocket luff.

Your comments on weight are plain wrong. The rig itself is a little heavier, but the centre of gravity is lower. If the boat is designed for the easy rig from the start, it is lighter; much lighter in the case of a multihull.

Your comments on small and narrow boats are also wrong, as the boat (multihull with high righting moment) in the video shows. I don't know of any cruising boats that will sail at wind speed with as little fuss and as much safety as this.

Interpolating from a 35 year old tiny polytarp/scrap timber rig on a vinyl hull to a properly engineered modern rig is a big leap. I suggest you study the rig in the video, or sail on a balanced rig and you may see how things have changed.

regards,

Rob

Thanks for your comments, Rob.

I've never learned anything from winning an argument.

I enjoyed your video as well. How fast was the boat going?

I just don't understand why a boat with its sail laced to its mast has to be rigged while laying on its side.

Spiral lacing has been around for a very long time and it seems to be the cheapest way to hold the luff of a main to the mast.

Part of my thought was that, with lacing, the luff of the sail is free to drift over to the lee side of the mast. This, I figured, would prevent the mast from being an ugly bump in front of the lee curve of the airfoil.

This, I also figured, would give an advantage for reaching at the expense of a few degrees upwind performance.

Also, with this type of rig, the jib is always in line with the main which I think would accentuate this advantage.

I've used lacing several times in admittingly small boats. I have never had trouble raising or lowering the sail.

After looking at the rig a little more carefully, I can see the problem with lacing the luff to the mast.

The jib does not go to the top of the mast and, therefore, the lacing must stop at the top of the jib, leaving the rest of the luff of the main unsecured and liable to sag off.

The solution I can offer is to run a vertical batten along the luff of the main from the top of the jib to the top of the main. This will help prevent that part of the main luff from sagging off too much, with the absence of lacing.

Its a Dutch development of the lateen rig modified by omitting the masts, with the yard arms of the lateens being stepped in thwarts. By this process, the yards became raked masts. Lateen sails mounted this way were known as leg-of-mutton sails in English. It's almost a complete reversal of Brian Eiland's aftmast design.

After looking at the rig a little more carefully, I can see the problem with lacing the luff to the mast.

The jib does not go to the top of the mast and, therefore, the lacing must stop at the top of the jib, leaving the rest of the luff of the main unsecured and liable to sag off.

The solution I can offer is to run a vertical batten along the luff of the main from the top of the jib to the top of the main. This will help prevent that part of the main luff from sagging off too much, with the absence of lacing.

Bob

G'day,

The jib stops it happening, but even without a jib, the tapered mast means it is a pretty loose fit at the top. No problem with a straight mast and parrel beads.The batten works for small boats, but not big ones. I sail off a beach, so tipping it on it's side is no big deal.

The boat in the video is doing 12-15 knots, the same as the windspeed. Sails are pretty ordinary and the mast could have been stiffer. Not bad for a heavy cruiser, though.

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